Subsurface chills to improve railcar knuckle formation

ABSTRACT

A method for manufacturing a railcar coupler knuckle includes, before casting, positioning an external chill within a cope mold portion and a drag mold portion offset from and adjacent internal walls of a pulling face and a throat of the cope and drag mold portions, thus producing a casting with reduced micro-shrinkage in at least the throat, a high-stress section of the casting. Use of subsurface chills produces an improved surface with fewer inclusions when compared to an equivalent surface produced in a process without use of a subsurface chill. The external chill may be a cone chill of a larger size to improve cooling and solidification at and below the surface. The external chill may also be a cylindrical and/or oblong chill with a tapered design that may correspond to the internal walls of the cope and drag mold portions between the pulling face and the throat.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/333,035 filed Dec. 21, 2011, which is related to U.S. patentapplication Ser. No. 12/979,967 (“the '967 application”), filed Dec. 28,2010 and entitled “Knuckle Formed Through The Use of Improved Externaland Internal Sand Cores and Method of Manufacture” (now U.S. Pat. No.8,408,407) all of which are hereby incorporated by this reference intheir entirety.

BACKGROUND

1. Technical Field

The present embodiments relate generally to the field of railroadcouplers, and more specifically, to the casting of railcar couplerknuckles using subsurface chills to reduce micro-shrinkage in ahigh-stress area of the casting.

2. Related Art

Railcar couplers are disposed at each end of a railway car to enablejoining one end of such railway car to an adjacently disposed end ofanother railway car. The engageable portion of each of these couplers isknown in the railway art as a knuckle.

Typically, a knuckle is manufactured by a mold—usually made of sand—andseveral cores that are disposed within the mold. The mold shapes theoutside of a casting. The cores are disposed to shape the inside oroutside of a casting. Without the internal cores, the casting would bemade of solid metal. The outside cores help shape the exterior of thecasting. The internal cores commonly are referred to as a finger core inthe front portion of the knuckle, a pivot pin core in the center of theknuckle, and a kidney core at the rear of a knuckle, and form thecavities in the knuckle upon casting.

During the casting process itself, the interrelationship of the mold andthe internal cores make the difference in producing a satisfactoryrailway coupler knuckle. Many knuckles fail from internal and/orexternal inconsistencies in the metal throughout the thickness of theknuckle. If one or more cores move during the casting process, then someknuckle walls may end up thinner than others, resulting in offsetloading and, in turn, in an increased failure risk during use of theknuckle.

The external features of a coupler knuckle should meet railroad industrystandards both because of initial acceptance of the knuckle and for itssuccessful performance in service. External features of a knuckle (7 inFIG. 3) that must be formed properly for successful knuckle performancein service include a pulling face contour (30 in FIG. 3) and a throat(42 in FIG. 3). The pulling faces of mating couplers contact each otherwhen freight cars are coupled together and transmit the forces pullingthe train. These pulling forces can be substantial. Moments of forcefrom the pulling face converge on the throat, a part of the knuckle thatoften fails because of the amount of force and the thinning of thethroat area between the surface and a C-10 pin hole (38 in FIG. 3). Forthis reason, railroad industry standards exist that specify the shape ofthe pulling face contour and recommended practices for forming thecoupler. Inconsistent or out of tolerance pulling face contours canresult in poor coupling/uncoupling performance of the coupler or indetrimental load paths for the pulling load. One patent that discussesthe importance of the proper performance of the pulling face is U.S.Pat. No. 7,337,826 entitled “Railway Car Coupler Knuckle Having ImprovedBearing Surface” (the '826 patent). The '826 patent describes techniquesfor casting a knuckle coupler with an enhanced bearing surface. The '826patent, however, does not address the imperfections that can form on orbelow the knuckle surface during casting.

Coupler knuckles are generally manufactured from cast steel or alloys.By way of example, when a molten metal is introduced into a mold duringcasting, it is prone to shrinking as it cools and solidifies. This isknown as “shrinkage” or “micro-shrinkage” and occurs because most metalsare less dense as a liquid than as a solid. Shrinkage may occur on theoutside of the casting, the inside of the casting, or both. Shrinkagemay lead to the knuckle forming shrinkage defects and/or solidificationrelated defects, and/or even the formation of a void in certain portionsof the knuckle. This could cause premature wear on the coupler to orresult in premature fatigue and/or failure.

One technique used to overcome micro-shrinkage is the inclusion ofrisers (255 in FIG. 4) in the mold. The risers feed the volumes of thecasting that are prone to shrinkage with additional casting material asthe casting cools. However, once the knuckle is cast, the risers must beremoved, typically by surface grinding. This may cause damage to theknuckle's surface and cause the knuckle to prematurely fatigue and/orfail. Moreover, risers and/or large ingates (256 in FIG. 4), e.g.,material that connects the risers to the casting, are limited bylocation in their ability to provide for a uniform thickness throughoutthe casting, maintain precise part profile, and they lose theireffectiveness in areas farther away from the riser. Other benefits anddrawbacks of using riser systems are discussed in the '967 application.

Internal and external metal chills have also been used to help removeheat from the poured metal in the location of the chill in order topromote and direct solidification and limit the amount of shrinkage inthe vicinity of the small area in which they are located. Sometimeschills can alleviate the need to have as many risers or have ingateslocated as close to each other. However, there are some disadvantagesrelating to the use of chills including additional costs. Furthermore,the chills must usually be made of the same material as the casting andsometimes fail to fuse with the casting, or must be removed from thecast knuckle later. External chills become attached to the knucklesurface and require removal followed by extra finishing steps that notonly increase costs but can leave scars or defects on the surface of theknuckle casting. Use of chills takes much experimentation, and thereforefailure, before finding a solution with improved results that justifythe added cost and/or casting defects in certain parts of the knucklecasting. What is needed, therefore, is an improved chill and deploymentthereof to obtain the benefits of using chills without the above-listeddisadvantages.

BRIEF DESCRIPTION OF THE DRAWINGS

The system may be better understood with reference to the followingdrawings and description. The components in the figures are notnecessarily to scale, emphasis instead being placed upon illustratingthe principles of the invention. Moreover, in the figures,like-referenced numerals designate corresponding parts throughout thedifferent views.

FIG. 1 is a schematic illustration of a coupler knuckle manufacturingassembly that includes use of an opening for an external subsurfacechill (such as a cone chill) in the cope and the drag mold sections ofthe assembly.

FIG. 2 is a perspective view of an example knuckle formed from theknuckle manufacturing assembly of FIG. 1.

FIG. 3 is a top plan view of the knuckle of FIG. 2.

FIG. 4 is a plan view of a sand mold for casting multiple knuckles, themold for each of the knuckles including an external subsurface chill.

FIGS. 5A through 5C is an embodiment of the cone chill shown in FIG. 1and relative dimensions of the cone chill.

FIG. 6 is a pattern for creating the cope mold displayed in FIG. 1,including mounting the cone chill on a pattern plate near the pullingface and throat portions of the coupler knuckle pattern.

FIG. 7 is a pattern for creating the cope mold displayed in FIG. 1,including mounting an oblong-shaped chill on the pattern plate, theoblong-shaped chill corresponding to a surface between the pulling faceand throat portions of the coupler knuckle pattern.

FIG. 8 is four screenshots of simulation results provided by a computerthat tracks different regions of the coupler knuckle as the molten metalcools during the casting process using different external chills.

FIG. 9 is a flow chart of an exemplary method for forming cope and dragmold portions including external subsurface chills for casting a railcarcoupler knuckle.

FIG. 10 is a flow chart of an exemplary method for manufacturing a railcar coupler knuckle using external subsurface chills.

DETAILED DESCRIPTION

In some cases, well known structures, materials, or operations are notshown or described in detail. Furthermore, the described features,structures, or characteristics may be combined in any suitable manner inone or more embodiments. It will also be readily understood that thecomponents of the embodiments as generally described and illustrated inthe Figures herein could be arranged and designed in a wide variety ofdifferent configurations.

As discussed above, one technique used to address micro-shrinkage issuesis the addition of metal chills. Chills absorb and remove the heat fromthe poured metal in the location of the chill in order to promote (anddirect) solidification and limit the amount of shrinkage in the vicinityof the small area in which they are located. These may be externalchills, which may be placed along the mold walls at predeterminedlocations, or may be internal chills. Both external and internal chillswill be discussed briefly, and then the remainder of the disclosure willfocus on a particular type of external chill not before used in knucklemanufacturing.

Internal chills can be pieces of metal that are strategically placedinside the mold cavity and ultimately become part of the casting.Internal chills add cost because they must be made of the same material,or at least compatible, with the casting. Moreover, internal chills maynot fuse properly with the casting, thus causing premature failure orrequiring the casting to undergo a further finishing and/or repairprocess.

External chills, which become attached to a knuckle's surface, may leavescars or other defects on the surface that require the casted knuckle toundergo extra finishing operations such as grinding, which may adverselyaffect the knuckle's surface finish and increase the costs due to extralabor required. Due to manual application of external chills, externalchills can result in inconsistent quality or a variance in tolerance ofsurface finish or dimensions within the foundry. Sometimes personnelinadvertently neglect the installations of chills or place them in theincorrect location. Moreover, chills must be clean and free of rust orother impurities so as not to inhibit the solidification process.

Accordingly, disclosed herein is a process to use a subsurface, externalchill that is not attached, and therefore need not be removed from thesurface of the knuckle. Through extensive research and trial, asubsurface cone chill of a general shape and size was determined to bethe most effective at removing heat from the molten metal during castingin relation to improving the formation of the pulling surface of theknuckle. Variances in the cone chill will be apparent to one of skill inthe art that would achieve the same or similar benefits. For instance,the cone chill may be truncated or pointed at the top, although thetruncated feature helps to hold the chill in place vertically in a sandmold. Furthermore, an oblong and/or cylindrical chill that follows thecontour of a wall between a pulling face and as far back as a lockingface of the knuckle may provide similar beneficial results. More thanone chill may also be used in various embodiments along this surfacearea of the knuckle casting.

FIG. 1 is a schematic illustration of a coupler knuckle manufacturingassembly 100 that includes use of an external, subsurface chill 5 in thecope and the drag sections of the assembly. The knuckle manufacturingassembly 100 includes a cope mold section 110, a combined (or separate)pivot pin and kidney core 10 and 12 and a finger core 14 used in themanufacturing process and a drag mold section 150. The cope mold section110 and the drag mold section 150 include mold cavities 112 and 152,respectively, into which a molten alloy is poured to cast a couplerknuckle (FIGS. 2-3). Mold cavities 112 and 152 are configured tocorrespond to the desired external surfaces of the coupler knuckle to bemanufactured using cope and drag mold sections 110 and 150. The pivotpin and kidney cores 10 and 12 may be positioned within the cope or dragmold such as to be isolated from or connected with the finger core 14.

A completed knuckle 7 is shown in FIGS. 2-3. The finger core 14 formsthe internal surfaces of a front face 26, nose 28, pulling face 30, heel32 and flag hole 34 of the knuckle 7. The finger core 14 extends outwardfrom the center to produce the flag hole 34 on both the top and bottomof the nose 28. The pivot pin core 10 forms the central internalsurfaces, including the C-10 pin hole 38, hub 40 and throat 42. Thekidney core 12 forms the internal surfaces of a tail 46 of the knuckle7. The cope and drag mold portions further define perimeter boundariesof the outer surfaces of the knuckle 7, including but not limited tothose of the nose 28, the tail 46, a lock shelf 48, a locking face 50and the throat 42.

FIG. 4 shows use of the external, subsurface chill 5 in a cope mold 212configured to cast multiple knuckles simultaneously. As will beexplained in more detail, the chill 5 may be positioned offset from butnear the internal walls of each mold cavity near the C-10 pin hole 238,to thereby affect the solidification of the molten metal at and belowthe surface of each coupler knuckle 7 generally between the pulling face230 and the locking face 250. As will be made apparent, when “surface”is referred to herein with reference to improved solidification of theknuckle, “sub-surface” is included in the meaning of “surface” becausethe solidification is affected at and below the surface. The extent towhich the subsurface region is affected by a chill depends on the size,shape and positioning of the chill (FIG. 8). The larger and closer thesub-surface chill 5 is to a surface, the more subsurface area of thecasting will be cooled and receive directional solidification, and thusreduced micro-shrinkage. Directional solidification describessolidification that occurs from the farthest end of a casting and worksits way towards the sprue entrance, where metal flows into the mold. Thesubsurface chill 5 may likewise be included in a corresponding drag moldsection (not shown) for the coupler knuckle(s) 7.

The subsurface chill 5 may be of different sizes and shapes, somefunctioning better than others to cool the throat 42 of the couplerknuckle 7 as it is cast. From dynamic testing results and review ofsectioned castings using fracture analysis of failed surfaces, it wasdetermined that the throat 42 of the knuckle 7 was particularly subjectto poor performance due to micro-shrinkage. Micro-shrinkage shortens thelife of the knuckle significantly because the throat 42 is subjected tohigh cyclic stresses. By placing a chill near the C-10 pin hole location238 of the knuckle within the cope and drag molds 110 and 150, theinventors achieved significant reductions in micro-shrinkage and thelittle micro-shrinkage that remained was forced into less importantareas of the cast knuckle. Furthermore, there were much fewer surfaceinclusions, leaving an improved, smoother finish along the surfacebetween at least the pulling face 30 and the throat 42 of the knuckle 7when compared to an equivalent surface in a process without the use ofsubsurface chills.

The subsurface chill 5 is positioned near to but not touching thesurface of the casting, leaving a small gap of sand therebetween andthus obviating the need to remove the subsurface chill from the knuckleafter casting. The result of using a subsurface chill is preservation ofthe cast surface and precise dimensions of the cast knuckle. Through thetesting process, the design team determined that a much largersubsurface chill 5 than previously tested in experiments, together withcorrect positioning, produced a greater reduction in micro-shrinkage inthe surface areas generally adjacent the C-10 pin hole 238 of thecasting, including in the throat 42. While the micro-shrinkage was notalways completely eliminated, it was reduced sufficiently to passintense dynamic testing or was moved away from the high stress surfaces(e.g., the throat and pulling face surfaces). Table I below summarizesresults of dynamic testing with various surface and subsurface chills.

TABLE I Chill Description Location Result Rectangular Subsurface Littledifference in removing Block Chill micro-shrinkage Small TruncatedSubsurface Little difference in removing Cone Chill micro-shrinkageSmall Truncated Surface (Prior Removed micro-shrinkage Cone Chill ArtMethod) significantly; surface rough with inclusions Boolean ChillSurface (Prior Removed micro-shrinkage Art Method) significantly;surface rough with inclusions Large Truncated Subsurface Removedmicro-shrinkage Cone Chill significantly; few surface inclusions

The external chill finally selected as most effective was the largetruncated cone chill used as a subsurface chill. In one embodiment(shown in FIGS. 5A through 5C), the large cone chill includes a majordiameter (L₁) of at least approximately 2.7″, which may also be amounting surface 500, a minor diameter (L₂) of at least approximately2.0″ and a height (H₁) of at least approximately 2.5″. The angle α maybe about 75 to 85 degrees, for instance, about 81 degrees. This conechill has an approximate surface area of 28 in², an approximate volumeof 11 in³ and an approximate mass of 3.2 lbs. In other embodiments, eachof the above-recited dimensions may be increased or decreased byanywhere between about 0.2″ to 0.7″. Accordingly, the volume may belarger than about 10 in³ and the surface area of the mounting surface500 may be larger than about 4 in². The chill may be placed between ⅛″and 3/16″ offset from the surface of the casting at the closestpoint(s), such as shown as distance X in FIG. 4. Greater distances maybe used with varying degrees of success depending on the size of thesubsurface chill. This creates a wall of sand between the subsurfacechill and the casting of at least ⅛″ in thickness. If the wall of sandgets too thin, it could break and holes can form through which moltenmetal may attach the chill 5 to the casting surface. If the chill is toofar away from the casting surface, the beneficial thermodynamic effectsof the chill may not be realized.

The subsurface cone chill 5 may be made from a variety of materials,including but not limited to a variety of commercial grade steels. Whileother materials could be selected from which to make the chills such ascopper-beryllium, cast steel of general chemistries was chosen as it wasinexpensive for the foundry to acquire, is effective in chilling anddoes not require special segregation during use. The subsurface chills 5disclosed herein may also be made from cast gray iron or a combinationof gray iron and graphite flakes since the thermal conductivity of castgray iron is primarily a function of the graphite flake content.

External chills or chill cores may also be made of non-metallic materialwith varying degrees of success. For instance, the subsurface chill 5may be made of Silicon carbide or graphite or at least portions of thechill 5 may be made from high-density sands such as zircon or chromiteor their respective derivatives. Graphite is desirable because itprovides higher cooling rates due to its high levels of thermalconductivity. Using a non-metallic or mostly non-metallic chill may alsobe beneficial if the wall of sand does break because it won't attach tothe knuckle casting and surface grinding can be avoided or minimized.

FIGS. 6 and 7 show a coupler knuckle pattern 600 attached to a patternplate 602 for creating the cope mold 110 displayed in FIG. 1. Eachpattern 600 is mounted to a pattern plate 602 to stabilize the patternwithin a mold box, and to create the mold cavity 112 or 152 within thecope or drag mold section 110 or 150 used to cast the knuckle(s) 7. Thecone chill 5 of FIG. 6 may be mounted on the pattern plate 602 adjacentto and offset from a surface of the pattern near a C-10 pin hole 638 ofthe coupler knuckle pattern 600. The oblong, generally cylindrical chill5 of FIG. 7 may likewise be mounted on the pattern plate 602. The chillsare also positioned near the pulling face 630 and the throat 642 regionsof the pattern 600, and may, as in FIG. 7, be tapered and/or shaped suchas to correspond to the contour of these regions. These chills 5 mayinclude more than one chill in alternative embodiments.

The chills 5 are held horizontally in the location of mounting by theuse of small, vertical pins 635 set in the pattern plate on theperimeter of the major diameter of the chill 5. The pins may be quitesmall, from approximately 1/16″ to ⅛″ in diameter and about ¼″ to 1″high. Sand under the circumferential radius of the major diameter of thecone chills may secure the cone chills vertically. Other ways ofmounting the chill 5 to the pattern plate 602 are envisioned, forinstance with the use of a dowel or rod (not shown) and a correspondingchannel for receipt of the dowel or rod (not shown). Sand is packed intoand around the pattern 600 within a cope or drag mold box 110 or 150,including the subsurface chill 5, to form the mold cavity 112 for theupper section 120 of the knuckle 7. The drag mold section 150 may besimilarly prepared. Each subsurface chill 5 may then be released fromthe pins 635 (or dowels or rods) when each pattern 600 is removed fromthe molds, leaving the subsurface chills 5 in each respective mold whileit cures, after which the molds are prepared for casting.

Because the chill is mounted on the pattern plate 602, when the pattern600 is removed, the chill is exposed at the surface. Accordingly, whenthe cope mold section 110 is closed on top of the drag mold section 150,the chills from each section 110 and 150 may come into contact with eachother, making an effective chill of twice the size, thus improving thecooling affects provided to the casting surface. In addition, oralternatively, the chills may be aligned with and adjacent each other,whether or not they come into contact.

FIG. 8 includes four screenshots of simulation results provided by acomputer program that tracks different regions of the coupler knuckle asthe molten metal cools during the casting process using different chills5. The “Base” screenshot indicates a baseline in which no chill wasused, for comparison with those examples that use a chill. The darkerareas in the screenshots are more likely to have defects. The BooleanCone and Small Subsurface Cone examples include significantly more darkareas near the pulling surface of the knuckle when compared with that ofthe Large Subsurface Cone, confirming the improvement through the use ofthe large cone chill 5.

The chilling effect of the subsurface cone chill 5 was simulated usingMagma5 from Magmasoft®. Not only did the simulation help in the analysisby defining the problem area around the throat 42 and the throatsurface, the software was also useful in developing the appropriatesize, location and shape of the chill without having to run multipleactual test runs in the foundry. Multiple simulations were made usingvarious sizes and shapes for the chill. The subsurface cone chill 5 ofthe above sizes and shapes were selected as being just large enough tomove the micro-shrinkage away from the surface without completelyfreezing off the directional solidification in the casting as largerchills might have done. Results of using the oblong, cylindrical chill 5of FIG. 7 are not shown in FIG. 8, but are at least at beneficial aswith the large subsurface chill. As can be seen, the larger subsurfacechill 5 improved solidification and included substantially fewer defectsbetween the pulling face and the lock shelf 48 of the coupler knuckle,including the throat 42 that lies therebetween.

FIG. 9 is a flow chart of an exemplary method for forming cope and dragmold portions including external subsurface chills for casting a railcarcoupler. The method includes, at block 900, placing at least oneexternal subsurface chill near a surface of a pattern for each moldportion between a pulling face and a throat of the pattern, the at leastone chill offset from and adjacent to a surface near a C-10 pin hole ofeach pattern. The method may further include, at block 910, mounting theat least one chill to a plate of each pattern to substantially preventshifting. The method also includes, at block 920, filling cope and dragmold boxes with sand, the mold boxes including respective patterns andthe mounted at least one chill, where each at least one chill is trappedwithin respective cope and drag mold portions with at least a thin wallof sand between the at least one chill and internal walls of the copeand drag mold portions defining the surface between the pulling face andthe throat. The method may further include, at block 930, compacting thesand into the mold boxes. The method may further include, at block 940,allowing the sand to cure. The method further includes, at block 950,removing each pattern from respective mold boxes while leaving the atleast one chill trapped within the cope and drag mold portions.

FIG. 10 is a flow chart of an exemplary method for manufacturing a railcar coupler knuckle using external subsurface chills as continued fromFIG. 9. The method includes, at block 1000, providing a cope moldportion and a drag mold portion, the cope and drag mold portions havinginternal walls defining at least in part perimeter boundaries of acoupler knuckle mold cavity. The method further includes, at block 1010,positioning the kidney, pivot pin and/or knuckle cores within cavitiesof the cope and/or drag mold portions, as required. The method furtherincludes, at block 1020, closing the cope and drag mold portions withthe cores and chills therebetween, the chills in the cope and drag moldportions optionally contacting each other across a centerline of themold cavity, which may double the size of the effective chill and itsimpact on cooling. The method further includes, at block 1030, fillingthe mold cavity with a molten metal, the molten metal solidifying afterfilling to form a casting with reduced micro-shrinkage at and below thesurface between and including the throat and/or pulling face of theknuckle. The chills may be large cone chills, oblong or cylindricalcones, or other chills. One longer chill may also be used that spans thecope and drag mold sections 112 and 152 instead of two separate chills5.

The terms and descriptions used herein are set forth by way ofillustration only and are not meant as limitations. Those skilled in theart will recognize that many variations can be made to the details ofthe above-described embodiments without departing from the underlyingprinciples of the disclosed embodiments. For example, the steps of themethods need not be executed in a certain order, unless specified,although they may have been presented in that order in the disclosure.The scope of the invention should, therefore, be determined only by thefollowing claims (and their equivalents) in which all terms are to beunderstood in their broadest reasonable sense unless otherwiseindicated.

1. (canceled)
 2. An assembly for casting a railcar coupler knuckle, comprising: a mold portion, the mold portion having internal walls defining at least in part perimeter boundaries of a coupler knuckle mold cavity including a front face portion, a nose portion, a pulling face portion, a heel portion, a throat portion, a tail portion, a lock shelf portion, and a locking face portion; at least one internal core placed to shape inside portions of the railcar coupler knuckle; and an external chill positioned within the mold portion, the external chill positioned between the front face portion and the tail portion of the mold portion and adjacent to the throat portion and the C-10 pin hole, the external chill offset from and adjacent the internal walls of the pulling face and the throat of the mold portion, wherein a wall of sand exists between the external chill and the internal walls of the coupler knuckle mold cavity; wherein a coupler knuckle is formable of metal from the mold portion that includes the chill, the coupler knuckle including an improved surface with reduced subsurface micro-shrinkage at a location of at least the throat of the coupler knuckle as compared to an equivalent surface cast in a process using a surface chill.
 3. The assembly of claim 2, wherein the improved surface extends substantially between the pulling face and a lock shelf of the coupler knuckle.
 4. The assembly of claim 2, wherein the chill is cone shaped.
 5. The assembly of claim 4, wherein the cone shaped chill is truncated cones including dimensions of a major diameter of more than 2.0″, a minor diameter of more than 1.50″ and a height of more than 1.85″.
 6. The assembly of claim 2, wherein the chill is comprised of one or more materials selected from the group consisting of: cast steel, cast gray iron, graphite, silicon carbide and a combination thereof.
 7. The assembly of claim 2, wherein the chill has a volume of at least ten cubic inches.
 8. The assembly of claim 2, wherein the chill has a maximum cross-section of about four square inches.
 9. The assembly of claim 2, wherein the chill has a mass of at least 3 pounds.
 10. The assembly of claim 2, further comprising at least two internal cores, a first internal core placed to define within the coupler knuckle a finger cavity and a second internal core placed to define within the coupler knuckle a pivot pin cavity and a kidney cavity.
 11. The assembly of claim 2, further comprising at least two internal cores, a first internal core placed to define within the coupler knuckle a finger cavity and pivot pin cavity and a second internal core placed to define within the coupler knuckle a kidney cavity.
 12. An assembly for creating a mold for casting a railcar coupler knuckle, comprising: a pattern plate; a pattern half attachable to the pattern plate with which to form a mold portion, the pattern half having exterior walls defining in the mold portion at least in part perimeter boundaries of a coupler knuckle mold cavity including a front face portion, a nose portion, a pulling face portion, a heel portion, a throat portion, a tail portion, a lock shelf portion, and a locking face portion; and an external chill releasably attached to the pattern plate positioned between the front face portion and the tail portion of the pattern and adjacent to the throat portion and the C-10 pin hole, the chill offset adjacent a throat region of respective pattern halves, the chill releasably attached to the pattern plate such that after the pattern is removed from the mold portion, the chill remains in the mold portion with a thin wall of sand between the chill and an internal wall of the mold portion.
 13. The assembly of claim 12, wherein the chill is releasably attached to the pattern plates with one or more vertical pins.
 14. The assembly of claim 12, wherein the chill includes a larger cross-sectional area on a side that is mounted to the pattern plate than the cross-sectional area taken at any other height.
 15. The assembly of claim 12, wherein the chill is cone shaped.
 16. The assembly of claim 15, wherein the cone shaped chill is a truncated cone including dimensions of a major diameter of more than 2.0″, a minor diameter of more than 1.50″ and a height of more than 1.85″.
 17. The assembly of claim 12, wherein the chill is comprised of one or more materials selected from the group consisting of: cast steel, cast gray iron, graphite, silicon carbide and a combination thereof.
 18. The assembly of claim 12, wherein the chill has a volume of at least ten cubic inches.
 19. The assembly of claim 12, wherein the chill has a maximum cross-section of about four square inches.
 20. The assembly of claim 12, wherein the chill has a mass of at least 3 pounds.
 21. An assembly for casting a railcar coupler knuckle, comprising: a mold portion, the mold portion having internal walls defining at least in part perimeter boundaries of a coupler knuckle mold cavity including a front face portion, a nose portion, a pulling face portion, a heel portion, a throat portion, a tail portion, a lock shelf portion, and a locking face portion; and at least one ingate; at least one riser preceding and engaged with the at least one ingate; and at least one internal core placed to shape inside portions of the railcar coupler knuckle; an external chill positioned within the mold portion, the external chill positioned between the front face portion and the tail portion of the mold portion and adjacent to the throat portion and the C-10 pin hole, the external chill offset from and adjacent the internal walls of the pulling face and the throat of the mold portion, wherein a wall of sand exists between the external chill and the internal walls of the coupler knuckle mold cavity. 